.bg{
	background: #cccccc;
	width: 100%;
	height:100%;
}
.m{
	width:300px;
	position:absolute;
	left:50%;
	top:50%;
	transform: translate(-50%,-50%);
	background: #ffffff;
}
.tb{
	width:300px;
	margin:25px 50px;
}
.tb tr {
	line-height: 30px;
}